The present invention relates generally to high current opening switches, and more specifically to a very low inductance, repetitive, high current opening switch for railguns.
Railguns are actively being considered as a primary component of a space based ballistic missile defense system. One of the limiting components in a railgun system has been identified as the opening switch. The opening switch is required to conduct high currents for long periods of time and then quickly open to commutate current into the railgun. In addition, the opening switch must be able to operate repetitively.
Railguns operate by using a very high electric current to create a very strong magnetic field. The vector cross product of the magnetic field with the current is called a Lorentz force. The Lorentz force can be used to propel an electrically conducting projectile between a pair of electrically conducting rails. The projectile experiences several 100,000's of g's as it accelerates down the railgun barrel and can obtain muzzle velocities of several kilometers per second.
The very high railgun currents place tremendous energy dissipation demands on the opening switch. The amount of switching energy dissipated by the opening switch is primarily a function of the switch inductance. The prior art includes actual and proposed railgun opening switches of successively lower switch inductances, but even lower switch inductances will be required to increase the system efficiencies of space based rapid fire railguns.
It is thus seen that there is a need for a railgun opening switch of lower switch inductance than has been thus far known in the art.
It is, therefore, a principal object of the present invention to provide a very low inductance, repetitive, railgun opening switch.
It is a feature of the present invention that the switch does not have to be offset relative to the rails to allow breech loading of the railgun.
It is another feature of the present invention that commutation time is reduced by increasing the rate of rise in resistance as the switch opens.
It is an advantage of the present invention that not all fingers of the brush modules conduct current during all times of a closed switch cycle, increasing the duty life of the brush modules.